There has heretofore been proposed a razor blade cartridge in which a water-soluble resin such as oxidized polyethylene has attached, penetrated, or dispersed to a part of a razor blade cartridge made of plastic in order to reduce the resistance between a part of a razor and the face (Patent Document 1).
Moreover, some composites in which mixing of a water-soluble resin and a water-absorbing resin allows a water-absorbing polymer to swell and various auxiliary agents to come off upon immersion in water may also be used as a smoother for wet shaving (Patent Document 2).
These products utilize impartation of lubricity to the surface of a resin caused by elution of a water-soluble resin under wet conditions. In these products, however, the compatibility between a water-soluble resin and a thermoplastic resin or between a water-soluble resin, a water-absorbing resin and a thermoplastic resin is low, so that the water-soluble resin is merely dotted on the surface of a resin composition. Therefore, although they are superior in lubricity at the initial stage, i.e. at the beginning of use, the water-soluble resin is lost during repetitive use, so that the lubricity will become lost.
A polymer composite to be used for wet shaving instruments, medical instruments, and so on has been disclosed (Patent Document 3). This polymer composite contains a water-insoluble polymer and a water-sensitive copolymer produced by polymerizing an alkylene oxide monomer with an epoxy functional monomer and maintains its lubricating property after repetitive use.
Even if an epoxy functional group is introduced into a polyalkylene oxide, however, the compatibility with a water-insoluble polymer is not enough and therefore the prevention of a water-soluble resin from coming off has been demanded in order to further maintain lubricity.
Moreover, since a water-soluble resin develops slime under wet conditions, improvement in touch feeling under wet conditions also has been demanded.